Question

Let’s say I started Linux process, in the background. It is not a daemon, just a utility.
If it gets SIGHUP, it would be killed.

I did not take the “nohup” precaution. It is taking already much longer time than I thought.
After 4 hours of running, ssh session might get disconnected. But I don’t want to lose the process.
I want to prevent it being killed by SIGHUP.

Is it possible to make the equivalent of

   signal(SIGHUP, SIG_IGN); 

to this process without restarting it ?

Thanks

Answer 1

Use disown(1)

disown: disown [-h] [-ar] [jobspec
…]
Remove jobs from current shell.

Removes each JOBSPEC argument from the table of active jobs.  Without
any JOBSPECs, the shell uses its notion of the current job.

Options:
  -a        remove all jobs if JOBSPEC is not supplied
  -h        mark each JOBSPEC so that SIGHUP is not sent to the job if
            the shell receives a SIGHUP
  -r        remove only running jobs

Detaching a process from terminal, entirely

“disown” is a bash builtin that
removes a shell job from the shell’s
job list. What this basically means is
that you can’t use “fg”, “bg” on it
anymore, but more importantly, when
you close your shell it won’t hang or
send a SIGHUP to that child anymore.
Unlike “nohup”, “disown” is used after
the process has been launched and
backgrounded.